-
PloS One 2016Approximately fifty percent of patients with acute myeloid leukemia can be cured with current therapeutic strategies which include, standard dose chemotherapy for...
BACKGROUND
Approximately fifty percent of patients with acute myeloid leukemia can be cured with current therapeutic strategies which include, standard dose chemotherapy for patients at standard risk of relapse as assessed by cytogenetic and molecular analysis, or high-dose chemotherapy with allogeneic hematopoietic stem cell transplant for high-risk patients. Despite allogeneic hematopoietic stem cell transplant about 25% of patients still succumb to disease relapse, therefore, novel strategies are needed to improve the outcome of patients with acute myeloid leukemia.
METHODS AND FINDINGS
We developed an immunotherapeutic strategy targeting the CD33 myeloid antigen, expressed in ~ 85-90% of patients with acute myeloid leukemia, using chimeric antigen receptor redirected T-cells. Considering that administration of CAR T-cells has been associated with cytokine release syndrome and other potential off-tumor effects in patients, safety measures were here investigated and reported. We genetically modified human activated T-cells from healthy donors or patients with acute myeloid leukemia with retroviral supernatant encoding the inducible Caspase9 suicide gene, a ΔCD19 selectable marker, and a humanized third generation chimeric antigen receptor recognizing human CD33. ΔCD19 selected inducible Caspase9-CAR.CD33 T-cells had a 75±3.8% (average ± standard error of the mean) chimeric antigen receptor expression, were able to specifically lyse CD33+ targets in vitro, including freshly isolated leukemic blasts from patients, produce significant amount of tumor-necrosis-factor-alpha and interferon-gamma, express the CD107a degranulation marker, and proliferate upon antigen specific stimulation. Challenging ΔCD19 selected inducible Caspase9-CAR.CD33 T-cells with programmed-death-ligand-1 enriched leukemia blasts resulted in significant killing like observed for the programmed-death-ligand-1 negative leukemic blasts fraction. Since the administration of 10 nanomolar of a non-therapeutic dimerizer to activate the suicide gene resulted in the elimination of only 76.4±2.0% gene modified cells in vitro, we found that co-administration of the dimerizer with either the BCL-2 inhibitor ABT-199, the pan-BCL inhibitor ABT-737, or mafosfamide, resulted in an additive effect up to complete cell elimination.
CONCLUSIONS
This strategy could be investigated for the safety of CAR T-cell applications, and targeting CD33 could be used as a 'bridge" therapy for patients coming to allogeneic hematopoietic stem cell transplant, as anti-leukemia activity from infusing CAR.CD33 T-cells has been demonstrated in an ongoing clinical trial. Albeit never performed in the clinical setting, our future plan is to investigate the utility of iC9-CAR.CD33 T-cells as part of the conditioning therapy for an allogeneic hematopoietic stem cell transplant for acute myeloid leukemia, together with other myelosuppressive agents, whilst the activation of the inducible Caspase9 suicide gene would grant elimination of the infused gene modified T-cells prior to stem cell infusion to reduce the risk of engraftment failure as the CD33 is also expressed on a proportion of the donor stem cell graft.
Topics: B7-H1 Antigen; Biphenyl Compounds; Bridged Bicyclo Compounds, Heterocyclic; Caspase 9; Cell Engineering; Cell Line, Tumor; Cell Proliferation; Cellular Reprogramming; Clinical Trials as Topic; Cyclophosphamide; Cytotoxicity, Immunologic; Genetic Vectors; Humans; Interferon-gamma; Leukemia, Myeloid, Acute; Lysosomal-Associated Membrane Protein 1; Myeloid Cells; Nitrophenols; Piperazines; Primary Cell Culture; Receptors, Antigen, T-Cell; Recombinant Fusion Proteins; Sialic Acid Binding Ig-like Lectin 3; Sulfonamides; T-Lymphocytes; Tumor Necrosis Factor-alpha
PubMed: 27907031
DOI: 10.1371/journal.pone.0166891 -
Oncotarget Nov 2016Activation of the IFN/STAT1 pathway is closely associated with drug response and recurrence of breast cancer treated by chemotherapy. The aim of the current study was to...
Activation of the IFN/STAT1 pathway is closely associated with drug response and recurrence of breast cancer treated by chemotherapy. The aim of the current study was to elucidate the molecular mechanisms involved upstream and downstream of this pathway in order to identify distinct entities that might be manipulated to improve treatment efficacy. Four breast cancer cell lines (T-47D, MCF7, MDA-MB-231 and HBCx-19 established from the eponymous PDX) were treated in vitro with mafosfamide, a DNA damage inducer. In two of these cell lines (MCF7 and HBCx-19), genotoxic treatment upregulated type I IFN expression leading to paracrine activation of IFN/STAT1 signaling pathway after 6-8 days. We show that STING, a well-characterized inducer of IFN in immune cells, is rapidly triggered in MCF7 cells under genotoxic stress and forms nuclear foci that co-localize with phosphorylated IRF-3 and γH2AX. STING silencing abrogated chemotherapy-induced type I IFN production and signaling and potentiated genotoxic treatment efficacy as it promoted cell death extent and delayed cell colony regrowth. Similar results were obtained after silencing PARP12, one selected gene of the IFN/STAT1 pathway fingerprint. In summary, this study provides the first demonstration of STING activation in breast cancer cells. Our data suggest that genotoxic-induced, STING-mediated type I IFN signaling is a cell-intrinsic mechanism of breast cancer cell survival and regrowth.
Topics: Breast Neoplasms; Cell Line, Tumor; Cell Survival; Cyclophosphamide; Female; Gene Expression Regulation, Neoplastic; Humans; Interferons; MCF-7 Cells; Membrane Proteins; Paracrine Communication; STAT1 Transcription Factor; Signal Transduction; Up-Regulation
PubMed: 27791205
DOI: 10.18632/oncotarget.12858 -
Genome Medicine May 2016The genetic origins of chemotherapy resistance are well established; however, the role of epigenetics in drug resistance is less well understood. To investigate...
BACKGROUND
The genetic origins of chemotherapy resistance are well established; however, the role of epigenetics in drug resistance is less well understood. To investigate mechanisms of drug resistance, we performed systematic genetic, epigenetic, and transcriptomic analyses of an alkylating agent-sensitive murine lymphoma cell line and a series of resistant lines derived by drug dose escalation.
METHODS
Dose escalation of the alkylating agent mafosfamide was used to create a series of increasingly drug-resistant mouse Burkitt's lymphoma cell lines. Whole genome sequencing, DNA microarrays, reduced representation bisulfite sequencing, and chromatin immunoprecipitation sequencing were used to identify alterations in DNA sequence, mRNA expression, CpG methylation, and H3K27me3 occupancy, respectively, that were associated with increased resistance.
RESULTS
Our data suggest that acquired resistance cannot be explained by genetic alterations. Based on integration of transcriptional profiles with transcription factor binding data, we hypothesize that resistance is driven by epigenetic plasticity. We observed that the resistant cells had H3K27me3 and DNA methylation profiles distinct from those of the parental lines. Moreover, we observed DNA methylation changes in the promoters of genes regulated by E2a and members of the polycomb repressor complex 2 (PRC2) and differentially expressed genes were enriched for targets of E2a. The integrative analysis considering H3K27me3 further supported a role for PRC2 in mediating resistance. By integrating our results with data from the Immunological Genome Project (Immgen.org), we showed that these transcriptional changes track the B-cell maturation axis.
CONCLUSIONS
Our data suggest a novel mechanism of drug resistance in which E2a and PRC2 drive changes in the B-cell epigenome; these alterations attenuate alkylating agent treatment-induced apoptosis.
Topics: Animals; Antineoplastic Agents; Basic Helix-Loop-Helix Transcription Factors; Burkitt Lymphoma; Cell Line, Tumor; Cyclophosphamide; DNA Methylation; Drug Resistance, Neoplasm; Epigenesis, Genetic; Histones; Humans; Mice; Polycomb Repressive Complex 2; Principal Component Analysis; Promoter Regions, Genetic
PubMed: 27146673
DOI: 10.1186/s13073-016-0305-0 -
Tumour Biology : the Journal of the... Aug 2016Obatoclax and ABT-737 belong to a new class of anticancer agents known as BH3-mimetics. These agents antagonize the anti-apoptotic members of Bcl-2 family. The Bcl-2... (Comparative Study)
Comparative Study
Obatoclax and ABT-737 belong to a new class of anticancer agents known as BH3-mimetics. These agents antagonize the anti-apoptotic members of Bcl-2 family. The Bcl-2 proteins modulate sensitivity of many types of cancer cells to chemotherapy. Therefore, the objective of the present study was to examine and compare the antileukemic activity of obatoclax and ABT-737 applied alone, and in combination with anticancer agent, mafosfamide and daunorubicin. The in vitro cytotoxic effects of the tested agents on human leukemia cells were determined using the spectrophotometric MTT test, Coulter electrical impedance method, flow cytometry annexin V-fluorescein/propidium iodide assay, and light microscopy technique. The combination index analysis was used to quantify the extent of agent interactions. BH3 mimetics significantly decreased the leukemia cell viability and synergistically enhanced the cytotoxic effects induced by mafosfamide and daunorubicin. Obatoclax affected the cell viability to a greater degree than did ABT-737. In addition, various patterns of temporary changes in the cell volume and count, and in the frequency of leukemia cells undergoing apoptosis, were found 24 and 48 h after the tested agent application. ABT-737 combined with anticancer agents induced apoptosis more effectively than obatoclax when given in the same combination regimen. The results of the present study point to the different antileukemic activities of obatoclax and ABT-737, when applied alone, and in combination with anticancer agents. A better understanding of the exact mechanisms of BH3 mimetic action is of key importance for their optional use in cancer therapy.
Topics: Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Cell Survival; Flow Cytometry; Humans; Indoles; Leukemia; Nitrophenols; Piperazines; Pyrroles; Sulfonamides
PubMed: 26880588
DOI: 10.1007/s13277-016-4943-z -
Magnetic Resonance in Medicine Sep 2016To facilitate decision making in the oncology clinic, technologies have recently been developed to independently inject and assess multiple anticancer agents directly in... (Comparative Study)
Comparative Study
PURPOSE
To facilitate decision making in the oncology clinic, technologies have recently been developed to independently inject and assess multiple anticancer agents directly in a patient's tumor. To increase the flexibility of this approach beyond histological readouts of response, contrast-enhanced MRI was evaluated for the detection of cell death in living tumors after injection.
METHODS
A six-needle arrayed microinjection device designed to provide head-to-head comparisons of chemotherapy responses in living tumors was used. Xenografted non-Hodgkin lymphoma tumors in athymic Nude-Foxn1(nu) mice were injected either with different doses of vincristine or with one needle each of vincristine, doxorubicin, bendamustine, prednisolone, mafosfamide, and a vehicle control. To assess drug responses, measurements of enhancement by T1-weighted contrast-enhanced MRI were made for individual sites at 24, 48, and 72 h after injection. For comparison, histological evaluations of cell death were obtained after tumor resection.
RESULTS
Measurements of MRI enhancement at injection sites showed a significant (P < 0.001) positive regression slope as a function of vincristine dose. Average MRI measurements were closely correlated with cell death by hematoxylin and eosin staining (R = 0.81; P = 0.001).
CONCLUSION
Contrast-enhanced MRI has the potential to replace or augment histological analyses of tumor responses to microinjected doses of chemotherapy agents with potential application in selecting optimal chemotherapy regimens. Magn Reson Med 76:946-952, 2016. © 2015 Wiley Periodicals, Inc.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Drug Monitoring; Lymphoma, Non-Hodgkin; Magnetic Resonance Imaging; Mice; Mice, Nude; Microinjections; Reproducibility of Results; Sensitivity and Specificity; Treatment Outcome
PubMed: 26362018
DOI: 10.1002/mrm.25978 -
Science Translational Medicine Apr 2015A fundamental problem in cancer drug development is that antitumor efficacy in preclinical cancer models does not translate faithfully to patient outcomes. Much of early...
A fundamental problem in cancer drug development is that antitumor efficacy in preclinical cancer models does not translate faithfully to patient outcomes. Much of early cancer drug discovery is performed under in vitro conditions in cell-based models that poorly represent actual malignancies. To address this inconsistency, we have developed a technology platform called CIVO, which enables simultaneous assessment of up to eight drugs or drug combinations within a single solid tumor in vivo. The platform is currently designed for use in animal models of cancer and patients with superficial tumors but can be modified for investigation of deeper-seated malignancies. In xenograft lymphoma models, CIVO microinjection of well-characterized anticancer agents (vincristine, doxorubicin, mafosfamide, and prednisolone) induced spatially defined cellular changes around sites of drug exposure, specific to the known mechanisms of action of each drug. The observed localized responses predicted responses to systemically delivered drugs in animals. In pair-matched lymphoma models, CIVO correctly demonstrated tumor resistance to doxorubicin and vincristine and an unexpected enhanced sensitivity to mafosfamide in multidrug-resistant lymphomas compared with chemotherapy-naïve lymphomas. A CIVO-enabled in vivo screen of 97 approved oncology agents revealed a novel mTOR (mammalian target of rapamycin) pathway inhibitor that exhibits significantly increased tumor-killing activity in the drug-resistant setting compared with chemotherapy-naïve tumors. Finally, feasibility studies to assess the use of CIVO in human and canine patients demonstrated that microinjection of drugs is toxicity-sparing while inducing robust, easily tracked, drug-specific responses in autochthonous tumors, setting the stage for further application of this technology in clinical trials.
Topics: Animals; Antineoplastic Agents; Biomarkers; Cell Line, Tumor; Cyclophosphamide; Dogs; Doxorubicin; Drug Delivery Systems; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; Lymphoma; Mice; Mice, Nude; Mice, SCID; Neoplasm Transplantation; Neoplasms; Prednisolone; TOR Serine-Threonine Kinases; Vincristine
PubMed: 25904742
DOI: 10.1126/scitranslmed.aaa7489 -
International Journal of Oncology Mar 2015To improve the efficacy of therapeutic options in chronic lymphocytic leukemia (CLL) an in vitro system to determine the response of mononuclear blood cells from blood... (Randomized Controlled Trial)
Randomized Controlled Trial
To improve the efficacy of therapeutic options in chronic lymphocytic leukemia (CLL) an in vitro system to determine the response of mononuclear blood cells from blood of patients was elaborated. The study combines four approaches, i.e., cell viability, apoptosis rate, differential scanning calorimetry (DSC), and immunoblotting to develop personalized therapy protocols based on the cell sensitivity to drug exposure of individual CLL patients. The complementary analyses were performed on 28 peripheral blood samples from previously untreated CLL patients before therapy. The induction and progress of apoptosis in CLL cells exposed in vitro to purine analogs combined with mafosfamide, i.e., cladribine + mafosfamide (CM) and fludarabine + mafosfamide (FM) were assessed using the above approaches. The changes in thermal profiles (decrease/loss of transition at 95±5˚C) coincided with an accumulation of apoptotic cells, a decrease in the number of viable cells, and differences in the expression of the apoptosis‑related protein PARP‑1. No significant changes were observed in the thermal profiles of nuclei isolated from CLL cells resistant to the treatment. The complementary assays revealed a strong relationship between both the in vitro sensitivity of leukemia cells to drugs and the clinical response of the patients, determined usually after the sixth course of treatment (after ~6 months of therapy). As a summary of studies followed by complementary tests, our findings demonstrate the value of in vitro exposure of CLL cell samples to drugs intended to treat CLL patients, before their administration in order to recommend the most suitable and effective therapy for individual patients.
Topics: Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Survival; Cells, Cultured; Cladribine; Cyclophosphamide; Drug Resistance, Neoplasm; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Leukocytes, Mononuclear; Male; Middle Aged; Treatment Outcome; Vidarabine
PubMed: 25572009
DOI: 10.3892/ijo.2015.2823 -
Cancer Research Oct 2014DNA repair processes are a key determinant of the sensitivity of cancer cells to DNA-damaging chemotherapeutics, which may induce certain repair genes as a mechanism to...
DNA repair processes are a key determinant of the sensitivity of cancer cells to DNA-damaging chemotherapeutics, which may induce certain repair genes as a mechanism to promote resistance. Here, we report the results of a screen for repair genes induced in cancer cells treated with DNA crosslinking agents, which identified the translesion polymerase η (PolH) as a p53-regulated target acting as one defense against interstrand crosslink (ICL)-inducing agents. PolH was induced by fotemustine, mafosfamide, and lomustine in breast cancer, glioma, and melanoma cells in vitro and in vivo, with similar inductions observed in normal cells such as lymphocytes and diploid fibroblasts. PolH contributions to the protection against ICL-inducing agents were evaluated by its siRNA-mediated attenuation in cells, which elevated sensitivity to these drugs in all tumor cell models. Conversely, PolH overexpression protected cancer cells against these drugs. PolH attenuation reduced repair of ICL lesions as measured by host cell reactivation assays and enhanced persistence of γH2AX foci. Moreover, we observed a strong accumulation of PolH in the nucleus of drug-treated cells along with direct binding to damaged DNA. Taken together, our findings implicated PolH in ICL repair as a mechanism of cancer drug resistance and normal tissue protection.
Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; DNA Replication; DNA-Directed DNA Polymerase; Drug Resistance, Neoplasm; Humans; Mice; Mice, Inbred NOD; Tumor Suppressor Protein p53; Up-Regulation
PubMed: 25125662
DOI: 10.1158/0008-5472.CAN-14-0953 -
Cancer Chemotherapy and Pharmacology Aug 2014The prognosis of patients with advanced-phase chronic myeloid leukemia (CML) remains dismal despite the availability of targeted therapies and allogeneic stem cell...
In vitro testing of drug combinations employing nilotinib and alkylating agents with regard to pretransplant conditioning treatment of advanced-phase chronic myeloid leukemia.
PURPOSE
The prognosis of patients with advanced-phase chronic myeloid leukemia (CML) remains dismal despite the availability of targeted therapies and allogeneic stem cell transplantation (allo-SCT). Increasing the antileukemic efficacy of the pretransplant conditioning regimen may be a strategy to increase remission rates and duration. We therefore investigated the antiproliferative effects of nilotinib in combination with drugs that are usually used for conditioning: the alkylating agents mafosfamide, treosulfan, and busulfan.
METHODS
Drug combinations were tested in vitro in different imatinib-sensitive and imatinib-resistant BCR-ABL-positive cell lines. A tetrazolium-based MTT assay was used for the assessment and quantification of growth inhibition after exposure to alkylating agents alone or to combinations with nilotinib. Drug interaction was analyzed using the median-effect method of Chou and Talalay, and combination index (CI) values were calculated according to the classic isobologram equation.
RESULTS
Treatment of imatinib-sensitive, BCR-ABL-positive K562 and LAMA84 cells with nilotinib in combination with mafosfamide, treosulfan, or busulfan resulted in synergistic (CI < 1), additive (CI ~ 1), and predominantly antagonistic (CI > 1) effects, respectively. In imatinib-resistant K562-R and LAMA84-R cells, all applied drug combinations were synergistic (CI < 1) at higher growth inhibition levels.
CONCLUSIONS
Our in vitro data warrant further investigation and may provide the basis for nilotinib-supplemented conditioning regimens for allo-SCT in advanced-phase CML.
Topics: Antineoplastic Combined Chemotherapy Protocols; Benzamides; Busulfan; Cell Proliferation; Cyclophosphamide; Drug Interactions; Drug Resistance, Neoplasm; Fusion Proteins, bcr-abl; Humans; Imatinib Mesylate; In Vitro Techniques; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Piperazines; Pyrimidines; Transplantation Conditioning; Tumor Cells, Cultured
PubMed: 25038611
DOI: 10.1007/s00280-014-2533-6